1648519 - clang-11 Windows instrumented builds need the PGO runtime path

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[(Away)]

In bug 1621552, we stopped passing the PGO runtime library to the linker because clang adds that library's full path as a dependentlib in object files, since clang-9.

However, in clang-11, the dependentlib no longer contains the full path but only the basename: https://github.com/llvm/llvm-project/commit/b8000c0ce84541c5b5535419234fb65ce77d6756

We'll need to set up the library path like before.

Comment 1

[(Away)]

glandium, I tried reverting the LIB piece of bug 1621552, which works for me locally on a native Windows build, but CI still can't find the PGO library. Does the cross-compile environment not use $LIB or something?

Comment 2

[Mike Hommey [:glandium]]

It does, but it needs a ; rather than a :. (; works on Windows too, no need to make it conditional on the host OS).

I wish we weren't using lld-link.exe directly...

Comment 3

[(Away)]

Attachment: Add back clang lib directory to LIB on Windows

clang 11 will stop using full paths in PGO dependentlib declarations, so we need to tell the linker where to find clang_rt.profile-x86_64.lib.

This is mostly a revert of the $LIB piece of bug 1621552, except we need to change the path separator since we've switched to cross-compiles in the meantime.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/96e224617b2f
Add back clang lib directory to LIB on Windows r=glandium

Comment 5

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/96e224617b2f